It was one of these:

Do I get another one or do folks recommend something else? The big plus for me was that it was so easy to clip on and off the rack, this is a must. Something a bit bigger wouldn't be so bad as it was a snug fit for all the stuff I used to pack in it. I ride 12 miles each way in all weathers so some degree of water resistance would be good. I can't find anything similar made by Ortlieb unfortunately.
All advice is welcomed.
Cheerio!